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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network66.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
66.167.0.0
Broadcast address
66.167.255.255
First usable
66.167.0.1
Last usable
66.167.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 42A70000 · Integer 1118240768 to 1118306303
Reverse DNS zone
167.66.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000010.10100111..00000000.0000000066.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01000010.10100111..00000000.0000000066.167.0.0
Broadcast01000010.10100111..11111111.1111111166.167.255.255
Split into smaller subnets/26
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

66.167.0.0/16 makes 1,024 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
166.167.0.0/2666.167.0.1 to 66.167.0.6266.167.0.6362
266.167.0.64/2666.167.0.65 to 66.167.0.12666.167.0.12762
366.167.0.128/2666.167.0.129 to 66.167.0.19066.167.0.19162
466.167.0.192/2666.167.0.193 to 66.167.0.25466.167.0.25562
566.167.1.0/2666.167.1.1 to 66.167.1.6266.167.1.6362
666.167.1.64/2666.167.1.65 to 66.167.1.12666.167.1.12762
766.167.1.128/2666.167.1.129 to 66.167.1.19066.167.1.19162
866.167.1.192/2666.167.1.193 to 66.167.1.25466.167.1.25562
966.167.2.0/2666.167.2.1 to 66.167.2.6266.167.2.6362
1066.167.2.64/2666.167.2.65 to 66.167.2.12666.167.2.12762
1166.167.2.128/2666.167.2.129 to 66.167.2.19066.167.2.19162
1266.167.2.192/2666.167.2.193 to 66.167.2.25466.167.2.25562
1366.167.3.0/2666.167.3.1 to 66.167.3.6266.167.3.6362
1466.167.3.64/2666.167.3.65 to 66.167.3.12666.167.3.12762
1566.167.3.128/2666.167.3.129 to 66.167.3.19066.167.3.19162
1666.167.3.192/2666.167.3.193 to 66.167.3.25466.167.3.25562
1766.167.4.0/2666.167.4.1 to 66.167.4.6266.167.4.6362
1866.167.4.64/2666.167.4.65 to 66.167.4.12666.167.4.12762
1966.167.4.128/2666.167.4.129 to 66.167.4.19066.167.4.19162
2066.167.4.192/2666.167.4.193 to 66.167.4.25466.167.4.25562
2166.167.5.0/2666.167.5.1 to 66.167.5.6266.167.5.6362
2266.167.5.64/2666.167.5.65 to 66.167.5.12666.167.5.12762
2366.167.5.128/2666.167.5.129 to 66.167.5.19066.167.5.19162
2466.167.5.192/2666.167.5.193 to 66.167.5.25466.167.5.25562
2566.167.6.0/2666.167.6.1 to 66.167.6.6266.167.6.6362
2666.167.6.64/2666.167.6.65 to 66.167.6.12666.167.6.12762
2766.167.6.128/2666.167.6.129 to 66.167.6.19066.167.6.19162
2866.167.6.192/2666.167.6.193 to 66.167.6.25466.167.6.25562
2966.167.7.0/2666.167.7.1 to 66.167.7.6266.167.7.6362
3066.167.7.64/2666.167.7.65 to 66.167.7.12666.167.7.12762
3166.167.7.128/2666.167.7.129 to 66.167.7.19066.167.7.19162
3266.167.7.192/2666.167.7.193 to 66.167.7.25466.167.7.25562
3366.167.8.0/2666.167.8.1 to 66.167.8.6266.167.8.6362
3466.167.8.64/2666.167.8.65 to 66.167.8.12666.167.8.12762
3566.167.8.128/2666.167.8.129 to 66.167.8.19066.167.8.19162
3666.167.8.192/2666.167.8.193 to 66.167.8.25466.167.8.25562
3766.167.9.0/2666.167.9.1 to 66.167.9.6266.167.9.6362
3866.167.9.64/2666.167.9.65 to 66.167.9.12666.167.9.12762
3966.167.9.128/2666.167.9.129 to 66.167.9.19066.167.9.19162
4066.167.9.192/2666.167.9.193 to 66.167.9.25466.167.9.25562
4166.167.10.0/2666.167.10.1 to 66.167.10.6266.167.10.6362
4266.167.10.64/2666.167.10.65 to 66.167.10.12666.167.10.12762
4366.167.10.128/2666.167.10.129 to 66.167.10.19066.167.10.19162
4466.167.10.192/2666.167.10.193 to 66.167.10.25466.167.10.25562
4566.167.11.0/2666.167.11.1 to 66.167.11.6266.167.11.6362
4666.167.11.64/2666.167.11.65 to 66.167.11.12666.167.11.12762
4766.167.11.128/2666.167.11.129 to 66.167.11.19066.167.11.19162
4866.167.11.192/2666.167.11.193 to 66.167.11.25466.167.11.25562
4966.167.12.0/2666.167.12.1 to 66.167.12.6266.167.12.6362
5066.167.12.64/2666.167.12.65 to 66.167.12.12666.167.12.12762
5166.167.12.128/2666.167.12.129 to 66.167.12.19066.167.12.19162
5266.167.12.192/2666.167.12.193 to 66.167.12.25466.167.12.25562
5366.167.13.0/2666.167.13.1 to 66.167.13.6266.167.13.6362
5466.167.13.64/2666.167.13.65 to 66.167.13.12666.167.13.12762
5566.167.13.128/2666.167.13.129 to 66.167.13.19066.167.13.19162
5666.167.13.192/2666.167.13.193 to 66.167.13.25466.167.13.25562
5766.167.14.0/2666.167.14.1 to 66.167.14.6266.167.14.6362
5866.167.14.64/2666.167.14.65 to 66.167.14.12666.167.14.12762
5966.167.14.128/2666.167.14.129 to 66.167.14.19066.167.14.19162
6066.167.14.192/2666.167.14.193 to 66.167.14.25466.167.14.25562
6166.167.15.0/2666.167.15.1 to 66.167.15.6266.167.15.6362
6266.167.15.64/2666.167.15.65 to 66.167.15.12666.167.15.12762
6366.167.15.128/2666.167.15.129 to 66.167.15.19066.167.15.19162
6466.167.15.192/2666.167.15.193 to 66.167.15.25466.167.15.25562
6566.167.16.0/2666.167.16.1 to 66.167.16.6266.167.16.6362
6666.167.16.64/2666.167.16.65 to 66.167.16.12666.167.16.12762
6766.167.16.128/2666.167.16.129 to 66.167.16.19066.167.16.19162
6866.167.16.192/2666.167.16.193 to 66.167.16.25466.167.16.25562
6966.167.17.0/2666.167.17.1 to 66.167.17.6266.167.17.6362
7066.167.17.64/2666.167.17.65 to 66.167.17.12666.167.17.12762
7166.167.17.128/2666.167.17.129 to 66.167.17.19066.167.17.19162
7266.167.17.192/2666.167.17.193 to 66.167.17.25466.167.17.25562
7366.167.18.0/2666.167.18.1 to 66.167.18.6266.167.18.6362
7466.167.18.64/2666.167.18.65 to 66.167.18.12666.167.18.12762
7566.167.18.128/2666.167.18.129 to 66.167.18.19066.167.18.19162
7666.167.18.192/2666.167.18.193 to 66.167.18.25466.167.18.25562
7766.167.19.0/2666.167.19.1 to 66.167.19.6266.167.19.6362
7866.167.19.64/2666.167.19.65 to 66.167.19.12666.167.19.12762
7966.167.19.128/2666.167.19.129 to 66.167.19.19066.167.19.19162
8066.167.19.192/2666.167.19.193 to 66.167.19.25466.167.19.25562
8166.167.20.0/2666.167.20.1 to 66.167.20.6266.167.20.6362
8266.167.20.64/2666.167.20.65 to 66.167.20.12666.167.20.12762
8366.167.20.128/2666.167.20.129 to 66.167.20.19066.167.20.19162
8466.167.20.192/2666.167.20.193 to 66.167.20.25466.167.20.25562
8566.167.21.0/2666.167.21.1 to 66.167.21.6266.167.21.6362
8666.167.21.64/2666.167.21.65 to 66.167.21.12666.167.21.12762
8766.167.21.128/2666.167.21.129 to 66.167.21.19066.167.21.19162
8866.167.21.192/2666.167.21.193 to 66.167.21.25466.167.21.25562
8966.167.22.0/2666.167.22.1 to 66.167.22.6266.167.22.6362
9066.167.22.64/2666.167.22.65 to 66.167.22.12666.167.22.12762
9166.167.22.128/2666.167.22.129 to 66.167.22.19066.167.22.19162
9266.167.22.192/2666.167.22.193 to 66.167.22.25466.167.22.25562
9366.167.23.0/2666.167.23.1 to 66.167.23.6266.167.23.6362
9466.167.23.64/2666.167.23.65 to 66.167.23.12666.167.23.12762
9566.167.23.128/2666.167.23.129 to 66.167.23.19066.167.23.19162
9666.167.23.192/2666.167.23.193 to 66.167.23.25466.167.23.25562
9766.167.24.0/2666.167.24.1 to 66.167.24.6266.167.24.6362
9866.167.24.64/2666.167.24.65 to 66.167.24.12666.167.24.12762
9966.167.24.128/2666.167.24.129 to 66.167.24.19066.167.24.19162
10066.167.24.192/2666.167.24.193 to 66.167.24.25466.167.24.25562
10166.167.25.0/2666.167.25.1 to 66.167.25.6266.167.25.6362
10266.167.25.64/2666.167.25.65 to 66.167.25.12666.167.25.12762
10366.167.25.128/2666.167.25.129 to 66.167.25.19066.167.25.19162
10466.167.25.192/2666.167.25.193 to 66.167.25.25466.167.25.25562
10566.167.26.0/2666.167.26.1 to 66.167.26.6266.167.26.6362
10666.167.26.64/2666.167.26.65 to 66.167.26.12666.167.26.12762
10766.167.26.128/2666.167.26.129 to 66.167.26.19066.167.26.19162
10866.167.26.192/2666.167.26.193 to 66.167.26.25466.167.26.25562
10966.167.27.0/2666.167.27.1 to 66.167.27.6266.167.27.6362
11066.167.27.64/2666.167.27.65 to 66.167.27.12666.167.27.12762
11166.167.27.128/2666.167.27.129 to 66.167.27.19066.167.27.19162
11266.167.27.192/2666.167.27.193 to 66.167.27.25466.167.27.25562
11366.167.28.0/2666.167.28.1 to 66.167.28.6266.167.28.6362
11466.167.28.64/2666.167.28.65 to 66.167.28.12666.167.28.12762
11566.167.28.128/2666.167.28.129 to 66.167.28.19066.167.28.19162
11666.167.28.192/2666.167.28.193 to 66.167.28.25466.167.28.25562
11766.167.29.0/2666.167.29.1 to 66.167.29.6266.167.29.6362
11866.167.29.64/2666.167.29.65 to 66.167.29.12666.167.29.12762
11966.167.29.128/2666.167.29.129 to 66.167.29.19066.167.29.19162
12066.167.29.192/2666.167.29.193 to 66.167.29.25466.167.29.25562
12166.167.30.0/2666.167.30.1 to 66.167.30.6266.167.30.6362
12266.167.30.64/2666.167.30.65 to 66.167.30.12666.167.30.12762
12366.167.30.128/2666.167.30.129 to 66.167.30.19066.167.30.19162
12466.167.30.192/2666.167.30.193 to 66.167.30.25466.167.30.25562
12566.167.31.0/2666.167.31.1 to 66.167.31.6266.167.31.6362
12666.167.31.64/2666.167.31.65 to 66.167.31.12666.167.31.12762
12766.167.31.128/2666.167.31.129 to 66.167.31.19066.167.31.19162
12866.167.31.192/2666.167.31.193 to 66.167.31.25466.167.31.25562
12966.167.32.0/2666.167.32.1 to 66.167.32.6266.167.32.6362
13066.167.32.64/2666.167.32.65 to 66.167.32.12666.167.32.12762
13166.167.32.128/2666.167.32.129 to 66.167.32.19066.167.32.19162
13266.167.32.192/2666.167.32.193 to 66.167.32.25466.167.32.25562
13366.167.33.0/2666.167.33.1 to 66.167.33.6266.167.33.6362
13466.167.33.64/2666.167.33.65 to 66.167.33.12666.167.33.12762
13566.167.33.128/2666.167.33.129 to 66.167.33.19066.167.33.19162
13666.167.33.192/2666.167.33.193 to 66.167.33.25466.167.33.25562
13766.167.34.0/2666.167.34.1 to 66.167.34.6266.167.34.6362
13866.167.34.64/2666.167.34.65 to 66.167.34.12666.167.34.12762
13966.167.34.128/2666.167.34.129 to 66.167.34.19066.167.34.19162
14066.167.34.192/2666.167.34.193 to 66.167.34.25466.167.34.25562
14166.167.35.0/2666.167.35.1 to 66.167.35.6266.167.35.6362
14266.167.35.64/2666.167.35.65 to 66.167.35.12666.167.35.12762
14366.167.35.128/2666.167.35.129 to 66.167.35.19066.167.35.19162
14466.167.35.192/2666.167.35.193 to 66.167.35.25466.167.35.25562
14566.167.36.0/2666.167.36.1 to 66.167.36.6266.167.36.6362
14666.167.36.64/2666.167.36.65 to 66.167.36.12666.167.36.12762
14766.167.36.128/2666.167.36.129 to 66.167.36.19066.167.36.19162
14866.167.36.192/2666.167.36.193 to 66.167.36.25466.167.36.25562
14966.167.37.0/2666.167.37.1 to 66.167.37.6266.167.37.6362
15066.167.37.64/2666.167.37.65 to 66.167.37.12666.167.37.12762
15166.167.37.128/2666.167.37.129 to 66.167.37.19066.167.37.19162
15266.167.37.192/2666.167.37.193 to 66.167.37.25466.167.37.25562
15366.167.38.0/2666.167.38.1 to 66.167.38.6266.167.38.6362
15466.167.38.64/2666.167.38.65 to 66.167.38.12666.167.38.12762
15566.167.38.128/2666.167.38.129 to 66.167.38.19066.167.38.19162
15666.167.38.192/2666.167.38.193 to 66.167.38.25466.167.38.25562
15766.167.39.0/2666.167.39.1 to 66.167.39.6266.167.39.6362
15866.167.39.64/2666.167.39.65 to 66.167.39.12666.167.39.12762
15966.167.39.128/2666.167.39.129 to 66.167.39.19066.167.39.19162
16066.167.39.192/2666.167.39.193 to 66.167.39.25466.167.39.25562
16166.167.40.0/2666.167.40.1 to 66.167.40.6266.167.40.6362
16266.167.40.64/2666.167.40.65 to 66.167.40.12666.167.40.12762
16366.167.40.128/2666.167.40.129 to 66.167.40.19066.167.40.19162
16466.167.40.192/2666.167.40.193 to 66.167.40.25466.167.40.25562
16566.167.41.0/2666.167.41.1 to 66.167.41.6266.167.41.6362
16666.167.41.64/2666.167.41.65 to 66.167.41.12666.167.41.12762
16766.167.41.128/2666.167.41.129 to 66.167.41.19066.167.41.19162
16866.167.41.192/2666.167.41.193 to 66.167.41.25466.167.41.25562
16966.167.42.0/2666.167.42.1 to 66.167.42.6266.167.42.6362
17066.167.42.64/2666.167.42.65 to 66.167.42.12666.167.42.12762
17166.167.42.128/2666.167.42.129 to 66.167.42.19066.167.42.19162
17266.167.42.192/2666.167.42.193 to 66.167.42.25466.167.42.25562
17366.167.43.0/2666.167.43.1 to 66.167.43.6266.167.43.6362
17466.167.43.64/2666.167.43.65 to 66.167.43.12666.167.43.12762
17566.167.43.128/2666.167.43.129 to 66.167.43.19066.167.43.19162
17666.167.43.192/2666.167.43.193 to 66.167.43.25466.167.43.25562
17766.167.44.0/2666.167.44.1 to 66.167.44.6266.167.44.6362
17866.167.44.64/2666.167.44.65 to 66.167.44.12666.167.44.12762
17966.167.44.128/2666.167.44.129 to 66.167.44.19066.167.44.19162
18066.167.44.192/2666.167.44.193 to 66.167.44.25466.167.44.25562
18166.167.45.0/2666.167.45.1 to 66.167.45.6266.167.45.6362
18266.167.45.64/2666.167.45.65 to 66.167.45.12666.167.45.12762
18366.167.45.128/2666.167.45.129 to 66.167.45.19066.167.45.19162
18466.167.45.192/2666.167.45.193 to 66.167.45.25466.167.45.25562
18566.167.46.0/2666.167.46.1 to 66.167.46.6266.167.46.6362
18666.167.46.64/2666.167.46.65 to 66.167.46.12666.167.46.12762
18766.167.46.128/2666.167.46.129 to 66.167.46.19066.167.46.19162
18866.167.46.192/2666.167.46.193 to 66.167.46.25466.167.46.25562
18966.167.47.0/2666.167.47.1 to 66.167.47.6266.167.47.6362
19066.167.47.64/2666.167.47.65 to 66.167.47.12666.167.47.12762
19166.167.47.128/2666.167.47.129 to 66.167.47.19066.167.47.19162
19266.167.47.192/2666.167.47.193 to 66.167.47.25466.167.47.25562
19366.167.48.0/2666.167.48.1 to 66.167.48.6266.167.48.6362
19466.167.48.64/2666.167.48.65 to 66.167.48.12666.167.48.12762
19566.167.48.128/2666.167.48.129 to 66.167.48.19066.167.48.19162
19666.167.48.192/2666.167.48.193 to 66.167.48.25466.167.48.25562
19766.167.49.0/2666.167.49.1 to 66.167.49.6266.167.49.6362
19866.167.49.64/2666.167.49.65 to 66.167.49.12666.167.49.12762
19966.167.49.128/2666.167.49.129 to 66.167.49.19066.167.49.19162
20066.167.49.192/2666.167.49.193 to 66.167.49.25466.167.49.25562
20166.167.50.0/2666.167.50.1 to 66.167.50.6266.167.50.6362
20266.167.50.64/2666.167.50.65 to 66.167.50.12666.167.50.12762
20366.167.50.128/2666.167.50.129 to 66.167.50.19066.167.50.19162
20466.167.50.192/2666.167.50.193 to 66.167.50.25466.167.50.25562
20566.167.51.0/2666.167.51.1 to 66.167.51.6266.167.51.6362
20666.167.51.64/2666.167.51.65 to 66.167.51.12666.167.51.12762
20766.167.51.128/2666.167.51.129 to 66.167.51.19066.167.51.19162
20866.167.51.192/2666.167.51.193 to 66.167.51.25466.167.51.25562
20966.167.52.0/2666.167.52.1 to 66.167.52.6266.167.52.6362
21066.167.52.64/2666.167.52.65 to 66.167.52.12666.167.52.12762
21166.167.52.128/2666.167.52.129 to 66.167.52.19066.167.52.19162
21266.167.52.192/2666.167.52.193 to 66.167.52.25466.167.52.25562
21366.167.53.0/2666.167.53.1 to 66.167.53.6266.167.53.6362
21466.167.53.64/2666.167.53.65 to 66.167.53.12666.167.53.12762
21566.167.53.128/2666.167.53.129 to 66.167.53.19066.167.53.19162
21666.167.53.192/2666.167.53.193 to 66.167.53.25466.167.53.25562
21766.167.54.0/2666.167.54.1 to 66.167.54.6266.167.54.6362
21866.167.54.64/2666.167.54.65 to 66.167.54.12666.167.54.12762
21966.167.54.128/2666.167.54.129 to 66.167.54.19066.167.54.19162
22066.167.54.192/2666.167.54.193 to 66.167.54.25466.167.54.25562
22166.167.55.0/2666.167.55.1 to 66.167.55.6266.167.55.6362
22266.167.55.64/2666.167.55.65 to 66.167.55.12666.167.55.12762
22366.167.55.128/2666.167.55.129 to 66.167.55.19066.167.55.19162
22466.167.55.192/2666.167.55.193 to 66.167.55.25466.167.55.25562
22566.167.56.0/2666.167.56.1 to 66.167.56.6266.167.56.6362
22666.167.56.64/2666.167.56.65 to 66.167.56.12666.167.56.12762
22766.167.56.128/2666.167.56.129 to 66.167.56.19066.167.56.19162
22866.167.56.192/2666.167.56.193 to 66.167.56.25466.167.56.25562
22966.167.57.0/2666.167.57.1 to 66.167.57.6266.167.57.6362
23066.167.57.64/2666.167.57.65 to 66.167.57.12666.167.57.12762
23166.167.57.128/2666.167.57.129 to 66.167.57.19066.167.57.19162
23266.167.57.192/2666.167.57.193 to 66.167.57.25466.167.57.25562
23366.167.58.0/2666.167.58.1 to 66.167.58.6266.167.58.6362
23466.167.58.64/2666.167.58.65 to 66.167.58.12666.167.58.12762
23566.167.58.128/2666.167.58.129 to 66.167.58.19066.167.58.19162
23666.167.58.192/2666.167.58.193 to 66.167.58.25466.167.58.25562
23766.167.59.0/2666.167.59.1 to 66.167.59.6266.167.59.6362
23866.167.59.64/2666.167.59.65 to 66.167.59.12666.167.59.12762
23966.167.59.128/2666.167.59.129 to 66.167.59.19066.167.59.19162
24066.167.59.192/2666.167.59.193 to 66.167.59.25466.167.59.25562
24166.167.60.0/2666.167.60.1 to 66.167.60.6266.167.60.6362
24266.167.60.64/2666.167.60.65 to 66.167.60.12666.167.60.12762
24366.167.60.128/2666.167.60.129 to 66.167.60.19066.167.60.19162
24466.167.60.192/2666.167.60.193 to 66.167.60.25466.167.60.25562
24566.167.61.0/2666.167.61.1 to 66.167.61.6266.167.61.6362
24666.167.61.64/2666.167.61.65 to 66.167.61.12666.167.61.12762
24766.167.61.128/2666.167.61.129 to 66.167.61.19066.167.61.19162
24866.167.61.192/2666.167.61.193 to 66.167.61.25466.167.61.25562
24966.167.62.0/2666.167.62.1 to 66.167.62.6266.167.62.6362
25066.167.62.64/2666.167.62.65 to 66.167.62.12666.167.62.12762
25166.167.62.128/2666.167.62.129 to 66.167.62.19066.167.62.19162
25266.167.62.192/2666.167.62.193 to 66.167.62.25466.167.62.25562
25366.167.63.0/2666.167.63.1 to 66.167.63.6266.167.63.6362
25466.167.63.64/2666.167.63.65 to 66.167.63.12666.167.63.12762
25566.167.63.128/2666.167.63.129 to 66.167.63.19066.167.63.19162
25666.167.63.192/2666.167.63.193 to 66.167.63.25466.167.63.25562

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.